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javascript/snippets/deep-get.md

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+---
+title: Get nested value in object based on array of keys
+type: snippet
+tags: [object]
+cover: mask-quiet
+dateModified: 2020-10-19T18:51:03+03:00
+---
+
+Gets the target value in a nested JSON object, based on the `keys` array.
+
+- Compare the keys you want in the nested JSON object as an `Array`.
+- Use `Array.prototype.reduce()` to get the values in the nested JSON object one by one.
+- If the key exists in the object, return the target value, otherwise return `null`.
+
+```js
+const deepGet = (obj, keys) =>
+  keys.reduce(
+    (xs, x) => (xs && xs[x] !== null && xs[x] !== undefined ? xs[x] : null),
+    obj
+  );
+```
+
+```js
+let index = 2;
+const data = {
+  foo: {
+    foz: [1, 2, 3],
+    bar: {
+      baz: ['a', 'b', 'c']
+    }
+  }
+};
+deepGet(data, ['foo', 'foz', index]); // get 3
+deepGet(data, ['foo', 'bar', 'baz', 8, 'foz']); // null
+```